Mg_0.9Mn_0.1In_xFe_2−x O₄ (x = 0.1 and 0.2) and Mg_0.9Mn_0.1Al_yFe_2−y O₄ (y = 0.1, 0.5 and 0.7) ferrites, with improved initial permeability and extremely low relative loss factor (RLF), were synthesized by the citrate precursor technique. Structural studies were made by using the x-ray diffraction technique and scanning electron microscopy (SEM), which confirm the formation of single-phase spinel structure. The size of the particle was of the order of ∼0.5 µm for the samples sintered at 1200 °C, which is smaller than that obtained for ferrite powders by the conventional ceramic method. The magnetic properties such as initial permeability and RLF with frequency, in the range 0.1–20 MHz, at different temperatures have been investigated. Initial permeability (μ_i) attains a very high value, 17342, for the In³⁺ doped ferrite series and for the Al³⁺ doped ferrite series the maximum value is 3785. The RLF was found to have low values and is of the order of 10⁻⁵–10⁻⁴ in the frequency range 0.1–20 MHz. In addition to this, an increase in the value of μ_i was observed with the rise in the temperature for all the series of ferrites.